The invention relates to a process for determining structural profiles produced in resist layers by polymerization or depolymerization.
The term resist is defined herein as a substance capable of being applied to the surface of a substrate in order to mask the part of the subtrate the substance covers, i.e., to protect the substrate against the attack of etching agents, chemical or galvanic metallizing baths, or the like. Resists, such as photosensitive resists, have the property that their solubility may be varied by exposure to UV, electron, x-ray or ionic radiation. During exposure, polymers are either formed and cross-linked (so-called negative layers), or polymers are broken up and converted into low molecular weight soluble compounds (so-called positive layers). This property of solubility variation in irradiated or non-irradiated areas of the resist surface is utilized for the production of a washout relief on the surface of the substrate. The structural profile of this washout relief depends on the material of the resist, the thickness of the resist layer, the duration and intensity of the radiation, and also on chemical development and fixation processes. While the material dependent effects may be largely controlled, the degree of cross-linking or fragmentation of the polymers obtained is uncertain. In the case of the known processes, the degree of cross-linking or fragmentation becomes visible only after chemical development. At that point, it is too late for correction.